I've done the first part of the attached question. 6lambda:1mu.

I don't think the hints make sense. c is perpendicular to a. How can it be on a plane with a and b and also be parallel to l as implied by r=a+kc?

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- Jun 16th 2010, 12:35 PMStuck ManVector line equations
I've done the first part of the attached question. 6lambda:1mu.

I don't think the hints make sense. c is perpendicular to a. How can it be on a plane with a and b and also be parallel to l as implied by r=a+kc? - Jun 17th 2010, 02:03 PMslider142
c is not parallel to l. r = a + kc means that each point of l is a resultant of a and some vector collinear with c. This is guaranteed becase a and c form a basis for the plane that l lies in.

This is akin to the vector equation of a line with standard basis: r = b + kx. - Jun 17th 2010, 02:58 PMPlato
- Jun 17th 2010, 03:10 PMPlato
Here is what you cannot read

The vector a x (a x b)=(a.b)a-(a.a)b is clearly perpendicular to**a**and as a linear combination of $\displaystyle a~\&~b$ it is in the plane of $\displaystyle a~,~b,~\&~O$. - Jun 17th 2010, 03:11 PMPlato
Here is what you cannot read

The vector a x (a x b)=(a.b)a-(a.a)b is clearly perpendicular to**a**and as a linear combination of $\displaystyle a~\&~b$ it is in the plane of a, b, & O. - Jun 18th 2010, 01:26 AMStuck Man
- Jun 18th 2010, 05:46 AMStuck Man
I have consulted another source which was helpful and can confirm that you are wrong slider142.

I had been thinking that c is a position vector so I can understand it all better now. slider142 also seems to have thought that c is a position vector.

I calculated that lambda:mu is 6:1 but the book says 1:6. Is the book wrong? I think I can do all the rest of the question. - Jun 19th 2010, 05:09 AMStuck Man
After 3 days still no one has given me any help.

Why is lambda:mu 1:6? Is the equation of line l r=i-2j+k+t(13i+4j-5k) as the book says? Why is p=-12i-6j+6k? Why is p not equal to b? - Jun 20th 2010, 05:08 AMStuck Man
I've finally done the question. Line l actually meets OB produced.